Metabolic Flexibility
The body's ability to switch between burning carbohydrates and fats — poor flexibility is linked to weight gain and insulin resistance.
Plain English
Patient-Friendly Explanation
Metabolic flexibility is your body's ability to switch efficiently between burning carbohydrates and fats for energy. When you are metabolically flexible, your body can easily adapt to different situations — burning carbs after a meal and switching to fat during a fast or exercise. Poor metabolic flexibility is linked to weight gain, insulin resistance, and difficulty losing weight.
Medical
Clinical Definition
Metabolic flexibility refers to the capacity of skeletal muscle mitochondria to switch substrate oxidation from predominantly lipid oxidation in the fasting state to glucose oxidation in the insulin-stimulated fed state. This is measured by the respiratory exchange ratio (RER) change between fasted and fed/insulin-stimulated conditions. Metabolic inflexibility, first described by Kelley et al. (1999), is characterised by impaired glucose uptake and reduced lipid oxidation capacity, and is a hallmark of insulin resistance, type 2 diabetes, and obesity.
Key Insight
Why It Matters
Improving metabolic flexibility through diet, exercise, and weight loss can enhance your body's ability to burn fat and maintain a healthy weight. Dr Joseph Wang at Accord Medical Clinic can help you understand and improve your metabolic health through personalised medical weight management.
Sources
Reviewed against standard medical references.
Medically reviewed by
Family Physician & Registered Acupuncturist, Accord Medical Clinic. MBBS (NUS), Graduate Diploma in Family Medicine (NUS), Graduate Diploma in Acupuncture (Singapore College of TCM).
Last reviewed: August 2026
This page is general health education, not medical advice. Whether any treatment is appropriate for you is a decision made in consultation after assessment.